In order to detect fake news, you should therefore always check the source of a message, if one is given. Who says so? First of all, check whether the source is a reputable one, if one is given. If you do not know the medium, google it. Has it ever distributed fake news in the past? Is the information also published by other sources you know?
Please also note the URL of the respective website. It may be a deliberate modification of a well-known platform – such as “derstandardnachrichten” to make it appear to be a credible medium.
If no source is given, it is best to google the claims to see if reliable websites are distributing them. For example, if a curfew is rumoured to be in effect, it would be a good idea to visit the websites of the ministries concerned or serious news sites.
A look at fact-checking platforms such as the Austrian Mimikama, US platforms such as Snopes or the website Politifact is also advisable. These repeatedly take up and check popular contributions and assertions in social media.